#!/bin/bash

# if stdin is coming from a pipe, run less
if [[ ! -t 0 ]]; then
    less -FX
# if there is only one arg and it is not a directory, less it
elif [[ "$#" -eq 1 && ! -d "$1" ]]; then
    less -FX "$1"
# if there are exactly two arguments and neither is a directory, diff them
elif [[ "$#" -eq 2 && ! -d "$1" && ! -d "$2" ]]; then
    diff --color=auto -u "$@"
# otherwise, run dir
else
    ls -lhAF --color=auto "$@"
fi